Motion evaluation system for golf swing and sports training

ABSTRACT

A golf learning aid is directed to improving an individual&#39;s golf swing by monitoring spine angle during a golf swing and alerting the individual when the spine angle varies outside of a predetermined maximum spine angle range during the swing. The system includes a device affixed to a top portion of a cap worn by the user, and an earpiece affixed to the device for playing an audible alert. The device employs a microcontroller, a tilt sensor and a system of buffering and filtering to provide real-time feedback on a user&#39;s spine angle during the swing. It is an additional feature of the system that the microcontroller generates an audible and repetitive tone as a metronome cadence when the microcontroller detects that the user is set up for a golf swing. The metronome cadence is provided to improve one&#39;s rhythm and timing in the golf swing and golf swing routine.

[0001] This application claims the benefit of U.S. ProvisionalApplication No. 60/404,258, “Golf Learning Aid,” John Clifford MillerIV, filed on Aug. 19, 2002, incorporated herein by reference.

BACKGROUND OF THE INVENTION

[0002] 1. Field of the Invention

[0003] The present invention relates to the golf learning aids, and inparticular to a learning aid directed to improving an individual's golfswing by monitoring spine angle during a golf swing and providingreal-time feedback to the individual when the spine angle varies outsideof a predetermined range of movement during the swing. The presentinvention further includes an audible metronome cadence to give thewearer a rhythm to improve his or her timing, golf swing and/or swingroutine.

[0004] 2. Description of the Related Art

[0005] The game of golf is hundreds of years old and there is aprofusion of patents covering various technical advances aimed atimproving one's golf game and lowering one's scores. Two criticalfactors in improving one's golf game are learning the fundamentals of aproper golf swing, and, once learned, repeatedly practicing the golfswing to create muscle memory of the proper swing.

[0006] It is commonly accepted that a proper golf swing involves, amongother things, a steady head height during the backswing through contactwith the ball on the forward swing. As shown in FIGS. 1 and 2, spineangle refers to the angle, θ, the spine forms with the vertical duringthe golf swing. The initial spine angle adopted in setting up for a golfshot will vary, depending on the club selected, the size of the golferand the contour of the ground. However, once a golfer has addressed thegolf ball and is ready to swing the club, the chosen angle should remainrelatively constant through the backswing and the downward swing untilcontact of the golf club with the golf ball.

[0007] A common problem among golfers is to straighten up the spineangle toward vertical during the backswing and/or downswing en route tostriking the golf ball. Varying the spine angle during the golf swingwill often result in a “topped” or “thin” shot, where only a top portionof the ball is struck, or alternatively a “heavy” or “fat” shot, wheretoo much of the ground behind the ball is struck. Both situations willresult in a poor golf shot.

[0008] In order to regularly execute a golf swing with a proper spineangle, a golfer must first learn the proper technique and thenrepeatedly practice the proper technique until the swing is engrainedinto the golfer's muscles. A problem however is that a golfer often doesnot realize that he or she is straightening up during the golf swing.Taking golf lessens where an instructor can point out spine anglemovement is an effective method for detecting the problem, but golflessens are expensive and an instructor is generally not around todetect spine angle movement when practicing the golf swing after thelesson is over. Taking video or photographic images of a golf swing isanother effective method for detecting the problem, but again, thisequipment is expensive and generally not convenient to carry or set upwhile practicing. Moreover, video and photographs are generally usedafter a practice session is over. They do not provide real-timeassistance with swing diagnosis.

[0009] Another method for detecting spine angle deviation during a golfswing is disclosed in U.S. Pat. No. 6,331,168 to Socci et al., entitled“Golf Training Head Gear For Detecting Head Motion And Providing AnIndication of Head Movement.” Biomechanical research has shown thatthere is a high correlation between spine angle and head position duringthe golf swing. Using this relationship, Socci discloses a system wherea device is affixed to the back of a hat worn by a golfer whilepracticing. The device includes a sensor capable of sensing the positionof a golfer's head during the golf swing, and providing an audibleindication when certain predetermined paths of head movement aredetected. While the system of Socci offers certain advantages overtraditional golf lessens and video equipment, improvements can be madeover Socci to further facilitate detection and correction of spine anglemovement to improve one's golf swing and golf game.

SUMMARY OF THE INVENTION

[0010] Embodiments of the present invention relate to a golf learningaid for improving an individual's golf swing by monitoring spine angleduring a golf swing and providing real-time feedback to the individualwhen the spine angle varies outside of a predetermined range of movementduring the swing. For this purpose, embodiments of the present inventioninclude a learning aid device affixed to a top portion of a cap worn bythe user, and an earpiece affixed to the device for playing an audiblealert.

[0011] In order to generate the alert, the device includes amicrocontroller and a tilt sensor. When the tilt sensor detects that auser's spine angle deviates outside of a predetermined range of movementduring a golf swing, the microcontroller generates the alert. Themicrocontroller further employs a system of buffering and filtering toeffectively eliminate motion data above and below predeterminedthresholds.

[0012] It is an additional feature of the present invention that themicrocontroller generates an audible and repetitive tone as a metronomecadence when the microcontroller detects that the user is set up for agolf swing. The present invention further offers the user an option toturn off the spine angle detection features, and to use the devicesolely to generate a metronome cadence for improving one's rhythm andtiming in the golf swing and golf swing routine.

BRIEF DESCRIPTION OF THE DRAWINGS

[0013] The present invention will now be described with reference to thedrawings, in which:

[0014]FIG. 1 is a prior art side view of a golfer preparing to swing agolf club;

[0015]FIG. 2 is a prior art side view of a golfer during a golf swing;

[0016]FIG. 3 is a top view of a system according to the presentinvention including a learning aid device mounted on a cap;

[0017]FIG. 4 is a side view of a system according to the presentinvention including a learning aid device mounted on a cap;

[0018]FIG. 5 is a front view of a system according to the presentinvention including a learning aid device mounted on a cap;

[0019]FIG. 6 is a top view of a learning aid device according to thepresent invention;

[0020]FIG. 7 is a top view of a learning aid device according to analternative embodiment of the present invention;

[0021]FIG. 8 is a block diagram of the internal components of thelearning aid device shown in FIG. 6;

[0022]FIG. 9 is a side view of a golfer wearing the system according tothe present invention with an enlarged view of the tilt sensor withinthe learning aid device;

[0023]FIG. 10 is a perspective view of a tilt sensor at a first angularorientation around the axis of sensitivity of the tilt sensor;

[0024]FIG. 11 is a perspective view of a tilt sensor at a second angularorientation around the axis of sensitivity of the tilt sensor;

[0025]FIG. 12 is a perspective view of a tilt sensor at a third angularorientation around the axis of sensitivity of the tilt sensor;

[0026]FIGS. 13A, 13B and 13C are front views of a tilt sensor accordingto an alternative embodiment of the present invention;

[0027]FIGS. 14A and 14B are a flow chart showing the operation of thecontrol program according to the present invention; and

[0028]FIG. 15 is a schematic representation of a baseline angle ±asensitivity angle.

DETAILED DESCRIPTION

[0029] The present invention now will be described more fully withreference to FIGS. 3 through 15, in which preferred embodiments of theinvention are shown. The present invention may, however, be embodied inmany different forms and should not be construed as being limited to theembodiments set forth herein; rather these embodiments are provided sothat this disclosure will be thorough and complete and will fully conveythe invention to those skilled in the art. Indeed, the invention isintended to cover alternatives, modifications and equivalents of theseembodiments, which are included within the scope and spirit of theinvention as defined by the appended claims. Furthermore, in thefollowing detailed description of the present invention, numerousspecific details are set forth in order to provide a thoroughunderstanding of the present invention. However, it will be clear tothose of ordinary skill in the art that the present invention may bepracticed without such specific details.

[0030] Referring now to FIGS. 3-5, there is shown a system according tothe present invention comprising a learning aid device 100 affixed to acap 102. The device may be permanently affixed to the cap 102, as byriveting or other known affixation methods. Alternatively, the device100 may be removably affixed to cap 102, as by Velcro® or other knownaffixation methods. It is understood that cap 102 may be any of avariety of hats and caps that are sufficiently snug on the wearer's headso that the cap remains stationary or relatively stationary on thewearer's head. While the device 100 is affixed to cap 102 in a preferredembodiment, it is understood that cap 102 may be omitted in alternativeembodiments, in which case, the device 100 may be mounted to head gearthat fits directly onto the wearer's head in a relatively stationary andsecure position.

[0031] In a preferred embodiment, the learning aid device 100 is locatedon the cap 102 so as to be positioned on the top portion of the wearer'shead when in use. It is understood that the learning aid device 100 maybe located at other positions on cap 102 in alternative embodiments.Moreover, in further embodiments, the device may be worn on otherlocations of the wearer's body, such as the back, waist or on a vestworn by the user. As explained hereinafter, the device 100 includes atilt sensor that is oriented generally along or parallel to the axis ofthe spine. It is understood that in embodiments where the device 100 ispositioned at locations other than the top of cap 102, the position ofthe tilt sensor within the device would vary accordingly to maintain theorientation of the sensor generally along or parallel to the axis of thespine.

[0032] As seen in FIG. 4, the system according to embodiments of thepresent invention further includes an audio output device 104 such as anearpiece which is affixed to the device 102 and is fashioned to be wornin the ear of the wearer. The earpiece 104 generates an audible alert inresponse to signals generated within the learning aid device 100 asexplained hereinafter. The earpiece 104 may be coupled to the device 100by electrical leads encased within a protective sheath. The sheath maybe provided on the interior of the cap, within the lining of the cap oron the exterior of the cap in alternative embodiments. It is understoodthat the electrical leads and sheath may be omitted in alternativeembodiments, and wireless protocols, such as for example Bluetoothwireless technology, may be used for communications between the device100 and earpiece 104.

[0033] Referring now to FIGS. 6 and 7, the learning aid device 100comprises an outer protective housing 106 preferably formed of plasticor metal. The housing preferably includes a detachable access door 108allowing access to the power supply for replacement or recharging of thepower supply as explained hereinafter. As shown in FIG. 6, the device100 further includes a thumbwheel 110 for adjusting the sensitivityangle of the device as explained hereinafter. As is also explainedhereinafter, embodiments of the present invention further include arepetitive audible metronome cadence for swing timing. A thumbwheel 112is provided for adjusting the tempo of the audible cadence. In theembodiment shown in FIG. 6, the volume for the audible cadence andaudible alert may be adjusted by a slide mounted on the earpiece 104.Thus, the system of the present invention may be used without disturbingothers who may be nearby. In embodiments of the present inventionomitting the audible cadence, as shown in FIG. 7, the volume control maybe provided on a thumbwheel 114. A display window 116 may further beprovided within the housing 106 in which are mounted one or more visualindicators, for example LEDs, for indicating an on/off state of thedevice, battery power level and other user information. On/off button117 may additionally be provided for manually turning the device 100 onand off.

[0034]FIG. 8 is a block diagram of the components of learning aid device100. Device 100 preferably includes a microcontroller 120, a tilt sensor122 and a power control circuit 126 having an on/of switch 117 andcontrolling a power supply 128. The device 100 may further include thesensitivity thumbwheel 110 and tempo adjust thumbwheel 112.

[0035] In embodiments of the present invention, microcontroller 120 maybe a microprocessor chip, such as for example the Cygnal® C8051F311.This chip includes a non-volatile program store such as a 16 k byteflash memory, and volatile memory such as a RAM having 1280 bytes ofon-chip data memory. It is understood that other types ofmicrocontrollers, having other on-board features, may be used inalternative embodiments.

[0036] Tilt sensor 122 is provided for sensing absolute angular positionrelative to the direction of gravity. If a golfer's spine angle changesduring the golf swing so that his or her head and upper body raiseupward (or lower downward), the resulting head and spine angle change isdetected by the tilt sensor 122 and communicated to the microcontroller120. In embodiments of the present invention, the tilt sensor may be anaccelerometer such as the Analog Devices ADXL202E, which outputs adigital signal proportional to the angular position of the sensorrelative to vertical. In one embodiment of the present invention, themicrocontroller 120 samples the tilt sensor 122 one hundred forty fivetimes a second. It is understood that the sample rate of the tilt sensor122 may be greater or lesser than that in alternative embodiments.

[0037] Referring now to FIGS. 9-12, the tilt sensor 122 has a majoraxis, referred to herein as the axis of sensitivity and referenced inthe figures as A_(s). In accordance with embodiments of the presentinvention, the axis of sensitivity of the tilt sensor is mounted at anangle, Φ, on the printed circuit board supporting the components withinthe device 100. In embodiments of the present invention, this angle Φmay be approximately 60° with respect to the printed circuit board, butit is understood that this angle Φ may be greater or lesser than 60° inalternative embodiments.

[0038] It is a feature of the present invention that, with the devicefixed on a wearer's head and with the sensor oriented at the angle Φ,the axis of sensitivity of the tilt sensor lies generally along orparallel to the axis of the spine. As the spine angle θ increases ordecreases, the angle between the axis of sensitivity and vertical willalso increase or decrease in same direction and in the same amount. Itis understood that while the angle between the axis of sensitivity andvertical will generally match the spine angle, there may be a fewdegrees difference in the respective angles.

[0039] In embodiments of the present invention, the digital output ofthe tilt sensor received by the microcontroller will vary depending onthe angle between the axis of sensitivity and vertical according to thecosine function. That is, as the angle between the axis of sensitivityand vertical varies from 0° to 90° (i.e., from vertical to horizontal),the output of the sensor will go from its maximum output to its minimumoutput according to the cosine function. Thus, the spine angle θ may becalculated from the angle between the axis of sensitivity and verticalby the microcontroller by taking the inverse cosine of the output fromthe tilt sensor. The values for spine angle θ for given sensor outputsmay be stored in a look-up table or calculated by algorithm. It isunderstood that the relationship between spine angle and the output fromthe tilt sensor may be other than inverse cosine in alternativeembodiments of the present invention.

[0040] It is a further feature of tilt sensor 122 that it is insensitiveto rotation about the axis of sensitivity. That is, for a given anglebetween the axis of sensitivity and vertical, the tilt sensor willoutput the same voltage regardless of the angular orientation of thetilt sensor around the axis of sensitivity, which angular orientationmay change as shown in FIGS. 10-12. As shown in FIGS. 10-12, the sensorhas an axis of sensitivity A_(s) and a width dimension, w, perpendicularto the axis of sensitivity. The insensitivity of the sensor to theorientation of the width dimension around the axis of sensitivity isadvantageous because, as a golfer swings a golf club, the golfer's headwill rotate around an axis of rotation of the head and spine. Thisrotation will also rotate the tilt sensor around the axis ofsensitivity. By aligning the axis of sensitivity along or parallel tothe spinal axis of rotation as described above, the tilt sensor will beinsensitive to the rotational position of the golfer's head as itrotates during the swing. Thus, a change in spine angle will at alltimes be indicated by a change in the angle between the axis ofsensitivity and vertical, regardless of the rotational position of thegolfer's head.

[0041] It is understood that the present invention may operate withsensors in which the output of the sensor is not independent of theangular orientation of the sensor around its axis. Such a tilt sensormay be used in combination with microcontroller 120 to account for theangular orientation of the golfer's head. For example, this may beaccomplished with a three-axis sensor in combination with geometryprocessing within the microcontroller.

[0042] It is understood that other tilt sensing devices may be used tosense the change in angle of a golfer's spine during a golf swing. Afurther example of a tilt sensor which is insensitive to orientationabout an axis of sensitivity is shown in FIGS. 13A-13C. In thisembodiment, the tilt sensor comprises a sealed cylindrical container 180having electrically insulated walls and having a conductive wire 182extending into the center of the container. The wire 182 has a first end184 suspended in the center of the container along the axis of rotationof the container, and a second end electrically coupled to a terminal188. The container further includes an electrically conductive band 190,made of for example copper, extending around the interior of thecontainer, and a conductive liquid 192, for example, a suitableelectrolyte or electrolytic fluid, in the bottom of the container. Theelectrolytic fluid can be an ionic liquid such as water or alcohol witha small amount of salt dissolved into it. The copper band 190 has upperand lower edges that lie in planes generally perpendicular to thedirection of gravity. The copper band is also electrically coupled to asecond terminal 193 via a second wire 194.

[0043] When the container is upright relative to gravity, the surface ofthe liquid lies in contact with a lower portion of the copper band, orlies just below the copper band as shown in FIG. 13A. However, when thecontainer is tipped at an angle as shown in FIG. 13B, the liquid willcontact a portion of the copper band. As the liquid is conductive,contact of the liquid with the copper band and wire 182 will change theresistance measured between the first and second terminals 188 and 193.As the tilt of the container increases, for example from the positionshown in FIG. 13B to the position shown in FIG. 13C, more liquid willcontact the copper band around the circumference of the copper band, andconsequently, the resistance measured between terminals 188 and 193 willdecrease further. Based on the electrical properties of the materialsused, the resistance measured across terminals 188 and 193 can becorrelated to an angle of the container relative to the direction ofgravity. The actual angle can then be determined based on the knowncorrelation through a look-up table or by appropriate algorithm.

[0044] By mounting the sensor 122 shown in FIGS. 13A-13C on printedcircuit board in a position so that the axis of rotation of thecontainer (the axis of sensitivity) lies generally along or parallel tothe axis of the spine, the sensor 122 can identify changes in spineangle as the golfer raises up or lowers down during a golf swing. As thecontainer is circular, it will be insensitive to rotation about the axisof sensitivity.

[0045] The container sensor shown in FIGS. 13A-13C for measuring achange in resistance can be converted into a sensor for measuring achange in capacitance in the same manner by locating the copper band 190on the exterior of the container 180 as opposed to the interior of thecontainer. Such a capacitive sensor may also be used to sense a changein spine angle according to the present invention.

[0046] It is understood that other sensors, including otheraccelerometers and gyroscopes, may be used to sense spine angle inalternative embodiments.

[0047] Power supply 128 may be a conventional 3 volt lithium coin cell,however it is understood that batteries supplying more or less voltagemay be used in alternative embodiments. Moreover, other power sourcesmay be used including rechargeable batteries, such as nickel cadmium,nickel metal hydride and lithium ion batteries, and renewable batteriessuch as solar powered cells. Combinations of these power sources may beused as well. As indicated above, the power supply may be removed andreplaced via access door 108 in the device housing 106. The voltage frompower supply 128 is preferably regulated to a microcontroller voltageof, for example, 3 volts by a voltage converter.

[0048] Power to the microcontroller and other components may becontrolled by power control circuit 126 and the on/off switch 117 inconjunction with microcontroller 120. In preferred embodiments, uponmanual activation of on/off switch 117 to turn on the device, the powercontrol circuit 126 causes a voltage to be supplied from the powersupply to the microcontroller and other components. It is understoodthat turning on of the device may be accomplished by other methods. Forexample, the device may include a motion sensor (which may be the tiltsensor or a separate motion sensor) which turns on the device uponsensing motion of the device. This method may operate in addition to orinstead of on/off switch 117.

[0049] The device can be turned off when in an active state byactivating the on/off switch 117. Alternatively, the microcontroller canturn off power supply if no motion is detected for a predeterminedperiod of time, for example, 10 minutes.

[0050] The audio output device 104 is provided to output an audible toneto the wearer. It is understood that in alternative embodiments, otherindicators capable of generating perceptible indications of an alertand/or a metronome cadence as described hereinafter may substitute forthe audio output device 104. Such alternative indicators may includevisual indicators and pressure indicators that apply light, perceptiblecontact to an area of the user's body. The indicators may additionallyor alternatively provide a perceptible indication by buzzing andvibration.

[0051] Device 100 is fabricated, tested and calibrated first byassembling the microcontroller and other device 100 electronics onto aprinted circuit board and then performing electrical testing of thecircuit board for example on an in-circuit test (ICT) fixture.Thereafter, microcontroller is connected to a computer and the controlprogram is downloaded from the computer to the microcontrollernon-volatile memory. The control program, explained in greater detailbelow, includes a calibration subroutine for calibrating the offset andgain of the tilt sensor signal. In preferred embodiments, the tiltsensor (mounted at an angle on the printed circuit board) should behorizontal during the calibration process.

[0052] The operation of the control program loaded in the non-volatilememory will now be explained with reference to the flow chart shown inFIGS. 14A and 14B. After the device is turned on in a step 200, forexample by manual activation of switch 117, the device goes into a readystate in step 202. From the ready state, the microcontroller performstwo processes concurrently. In one process, shown in step 204, themicrocontroller continuously monitors whether a predetermined period oftime has passed where there has been no activity. The microcontrollerincludes a clock that monitors the passage of time. The control programcontinuously loops between steps 202 and 204. If at any time themicrocontroller detects the passage of a preset time period, for example10 minutes, without any activity, then the control program jumps out ofthe loop and the device is shut off in a step 206.

[0053] Concurrently with the timeout check, the control program causesthe microcontroller to determine the current spine angle θ (FIG. 9)indicated by the angle between the axis of sensitivity and the verticalin a step 208. The microcontroller 120 receives a digital signal fromthe tilt sensor 122 relating to spine angle one hundred forty five timesa second (in one embodiment). Six sensor samples may be averaged andresampled at twenty times a second. The actual angle may be calculatedfrom a look-up table or algorithm as described above according to theinverse cosine of the sensor 122 output.

[0054] The control program according to the present invention includes adata smoothing process as part of step 208. In particular, if the spineangle changes dramatically from one sensor sample to the next, this isthe result of bouncing, shuffling or fast motion other than a golfswing, and this data should be disregarded. In order to accomplish this,the control program causes the microcontroller to examine changes inspine angle between consecutive sensor samplings for the most recentnine spine angle entries stored in RAM. The microcontroller performs aneighth order low pass filter on the angle data. The low pass filterattenuates angle changes that occur above a predetermined frequency, forexample above 7 Hz. This information is then stored as a 32-entry LPFbuffer within the microcontroller RAM. It is understood that themicrocontroller may use more or less that the most recent nine dataentries, and may filter out data greater than or lesser than 7 Hz, inalternative embodiments.

[0055] If someone wearing the device is walking or standing in anupright position, the device 100 should not be monitoring for properspine angle. Likewise, if the wearer is bending over, for examplepicking up a golf ball or other item, the device 100 should not bemonitoring for proper spine angle. Therefore, in step 210, the controlprogram determines whether the spine angle θ is between a predeterminedmaximum and minimum angle corresponding to a possible ready position forswinging a golf club. In one embodiment of the present invention, theminimum spine angle can be between 5° and 15° and optimally around 10°,and the maximum spine angle can be between 70° and 90° and optimallyaround 90°. It is understood that the minimum and maximum spine anglescan be outside of the respective ranges set forth above in alternativeembodiments. If the current spine angle is not within the minimum andmaximum angles, the control program returns to the ready state 202.

[0056] In a step 212, the control program next checks to see whethermotion is below a threshold level. In particular, if the user of thedevice is moving around above a threshold level, he or she is not readyto perform a golf swing, and the device should not move to the armedstate. In order to check for motion above a threshold level, the controlprogram causes the microcontroller to examine changes in spine anglebetween consecutive sensor samplings for the previous 32 entries storedin the RAM LPF buffer. The microcontroller performs a second order highpass filter on the angle data in a 32 entry high pass filter buffer inRAM. The high pass filter attenuates angle changes that occur below apredetermined frequency, for example below 0.33 Hz. The control programthen sums the absolute values of the previous 32 entries in the highpass filter buffer. If the sum is above a predetermined limit, thisindicates spine angle movement above the threshold level, and thecontrol program returns to the ready state in step 202. If the sum ofthe angle changes is below the predetermined limit, this indicatesmovement below the threshold level and the program proceeds to a step214. In a preferred embodiment, the limit may vary from 22.5° to 50°depending on the current spine angle. It is understood that the highpass filter may be set to filter data above or below 0.33 Hz, and thatthe predetermined limit may be set above or below 22.5° to 50°, inalternative embodiments.

[0057] In embodiments of the present invention, it is desirable to buildin a delay after an alert sounds to ensure that the action giving riseto the alert has been completed and multiple alerts do not sound as aresult of a single action. The control program therefore builds in adelay after an alert has sounded in a step 214. Once an alert hassounded, the time of the alert is stored in the microcontroller RAM. Instep 214, the control program checks to see if the predetermined periodof time since the last alert has passed. In one embodiment, that periodof time may be 4 seconds, but the delay period may be greater than orless than 4 seconds in alternative embodiments. If the time since thelast alert is less than the predetermined period of time, the controlprogram returns to the ready state of step 202.

[0058] If each of steps 210 through 214 are passed, that indicates thatthe wearer is set up for a golf swing. Accordingly, in a step 216, thecontrol program causes the current spine angle to be set as the baselineangle, ψ, as shown in FIG. 15. The baseline angle is used as the spineangle to be maintained during the ensuing golf swing. If the spine angledeviates from the baseline angle greater than a user-defined angularrange, as explained hereinafter, the alert will sound. The controlprogram allows the baseline angle ψ to vary from swing to swing, whichis desired because the baseline angle for a given swing will depend onseveral factors which can vary from swing to swing, including the clubselected and the incline of the ground on which the swing is beingperformed.

[0059] Referring still to FIG. 15, the present invention allows a wearerto select an angle, referred to herein as the sensitivity angle α, whichis added to the baseline angle ψ and subtracted from the baseline angleψ to define a maximum spine angle range for the golfer's spine during agolf swing. If the golfer deviates outside of the maximum spine anglerange during a golf swing, the alert will sound. The sensitivity angle αmay be set via thumbwheel 110. The sensitivity angle α is selected basedon the wearer's skill level. Relatively unskilled golfers who have notyet learned a consistent swing would want to set a relatively largesensitivity angle α to provide a large maximum spine angle range. Thus,they can execute a golf swing where their spine angle does varysomewhat, but allows them to practice and improve without the alertsounding on every swing. The alert would only sound when their spineangle is outside of the maximum spine angle range given by the baselineangle, ψ, plus and minus the sensitivity angle α they selected. On theother hand, relatively skilled golfers would want to set a relativelysmall sensitivity angle so that their spine angle must stay relativelyconstant or the alert will sound. In embodiments of the invention, thesensitivity angle may be set to as little as 4° and as high as 21°.Thus, when set at the minimum sensitivity angle, if the wearer deviateshis or her spine angle from the baseline angle more than 4° upwards ormore than 4° downward, the alert will sound. Similarly, when the maximumsensitivity angle is selected, if the wearer deviates his or her spineangle from the baseline angle more than 21° upwards or downwards, thealert will sound.

[0060] It is understood that the maximum and minimum sensitivity anglesmay be greater or lesser than 4° and 21°, respectively. Moreover, it isunderstood that manual controls may be provided on the device (notshown) to provide a maximum spine angle range that is not symmetricalabout the baseline angle ψ. For example, controls may be provided toallow a golfer to raise up toward vertical as much as 21° above thebaseline angle without the alert sounding, but lower down only 10° belowthe baseline angle without the alert sounding. Thus, the maximum spineangle range is 30°, but it is not symmetrical about the baseline angle.The device may also be configured to allow a greater motion below thebaseline angle than above the baseline angle.

[0061] Once the baseline angle is set in step 216, the device 100 goesinto an armed state in step 218. When in the armed state, it is afeature of the present invention to sound a metronome cadence. Themetronome cadence is an audible tone generated by the microcontroller120 and played through the earpiece 104. In addition to alerting thewearer that the device 100 is in the armed state, the tone is intendedto give the wearer a cadence and rhythm to improve his or her timing,golf swing and/or swing routine. The tempo of the metronome cadence maybe user adjusted via thumbwheel 112. In embodiments of the invention,the cadence may be as slow as 45 beats per minute and as fast as 95beats per minute. The tempo of the cadence may vary outside of thatrange in alternative embodiments of the invention.

[0062] There can be a setting on thumbwheel 112 or some other actuatorlocated elsewhere on the housing 106 which, when selected, turns off thespine angle detection features of the device 100. When used in thismode, the device 100 continuously sounds the metronome cadence which canbe played while practicing or playing a round, and used with woods,irons and while putting. When in this mode, the metronome cadence wouldcontinue to sound until turned off by the wearer.

[0063] Once in the armed state, in addition to sounding the metronomecadence, the microcontroller performs two additional processesconcurrently. In one process, shown in step 220, the microcontrollercontinuously monitors whether a predetermined period of time has passedwhere there has been no activity. The control program continuously loopsbetween steps 218 and 220. If at any time the microcontroller detectsthe passage of a preset time period, for example 10 minutes, without anyactivity, then the control program jumps out of the loop and the deviceis shut off in a step 222.

[0064] Concurrently with the timeout check, the control program executesa step 224 where the microcontroller determines a current spine angle(as described above with respect to step 208), and determines whetherthe current spine angle is outside of the maximum spine angle rangegiven by the baseline angle plus and minus the sensitivity angle asdescribed above. If so, then the control program causes microcontroller120 to sound an audible alert through the earpiece 104 in a step 226.The alert may differ in tone and/or duration from the metronome cadence.The duration of the audible alert may vary, but may be for example 1second. In the above-disclosed embodiment, the alert is sounded when thewearer's spine angle either increases or decreases from the baselineangle ψ greater than the sensitivity angle α. However, in alternativeembodiments, the system may monitor only when the baseline angledecreases greater than the sensitivity angle (i.e., the system onlychecks to see if the golfer rises up a certain amount during the golfswing). Alternatively, the system may be set up to detect only when thebaseline angle increases greater than the sensitivity angle.

[0065] If the spine angle detected is outside of the maximum spine anglerange in step 224, the metronome cadence may be turned off in a step228. It is understood that in alternative embodiments, step 228 may beskipped so that the metronome cadence stays on even if the alert sounds.This alternative is a separate embodiment from an embodiment where theuser has selected the mode where the spine angle detection system isturned off and the device functions solely as a metronome cadencesystem.

[0066] After performing steps 226 and 228, the control program returnsto the ready state in step 202. If the spine angle detected in step 224is within acceptable ranges, then steps 226 and 228 are skipped, and thecontrol program loops back to the armed state in step 218.

[0067] As is evident from the above-description, the present inventionmay be used as a learning aid to provide real-time feedback to improveone's golf game. In use, a wearer would initially set the desiredsensitivity angle, the tempo for the metronome cadence and/or the volumeof the alert and cadence. Then the wearer would go about his or hernormal practice routine. The device can be used to provide both cadenceand spine angle monitoring. Alternatively, when used only in metronomecadence mode, the device can provide a repetitive tone for improvingone's rhythm and timing.

[0068] Although the invention has been described in detail herein, itshould be understood that the invention is not limited to theembodiments herein disclosed. Various changes, substitutions andmodifications may be made to the disclosure by those skilled in the artwithout departing from the spirit or scope of the invention as describedand defined by the appended claims.

We claim:
 1. A golf learning aid capable of being worn by an individual,comprising: a sensor capable of sensing an angle formed between an axispassing generally through the individual's spine and vertical; a manualcontrol for the individual to select a maximum spine angle from a rangeof maximum allowable spine angles; an indicator for providing one ormore perceptible indications; a controller capable of: a) monitoringsaid sensor and determining whether said angle is greater than or lessthan said maximum spine angle, and b) sending information to saidindicator to produce a first indication when said angle is greater thanor less than said maximum spine angle.
 2. A golf learning aid as recitedin claim 1, said controller further being capable of sending informationto said indicator to produce a second indication, said second indicationbeing a metronome cadence repeating at a user-defined tempo.
 3. A golflearning aid as recited in claim 1, wherein the golf learning aid isworn on the individual's head.
 4. A golf learning aid as recited inclaim 1, said controller further capable of determining a time at whichthe individual appears ready to perform a golf swing, said controllersending said information to said indicator to produce said secondindication after said time.
 5. A golf learning aid as recited in claim2, further comprising an actuator for being actuated by the individual,the controller sending information to said indicator to continuouslyproduce said second indication upon actuation of said actuator by theindividual.
 6. A golf learning aid as recited in claim 1, saidcontroller further capable of determining a time at which the individualappears ready to perform a golf swing, said controller sending saidinformation to said indicator to produce said first indication when saidangle is outside of said maximum spine angle range after said time.
 7. Agolf learning aid as recited in claim 1, wherein said sensor is anaccelerometer capable of sensing acceleration in the direction ofgravity.
 8. A golf learning aid as recited in claim 1, wherein saidmaximum spine angle range is adjustable by the individual.
 9. A golflearning aid as recited in claim 1, wherein said indicator is a soundgenerator including an earpiece adapted to be worn in an ear of theindividual.
 10. A golf learning aid capable of being worn by anindividual in fixed position, comprising: a sensor capable of sensing anangle formed between an axis passing generally through the individual'sspine and vertical; an indicator for providing one or more perceptibleindications; a controller for receiving information from said sensor,said controller being capable of sending information to said indicatorto produce a first indication when said angle is outside of a maximumspine angle range, and said controller being capable of sendinginformation to said indicator to produce a second indication differentthan said first indication, said second indication being a metronomecadence repeating at a user-defined tempo.
 11. A golf learning aid asrecited in claim 10, said controller further capable of determining atime at which the individual appears ready to perform a golf swing, saidcontroller sending said information to said indicator to produce saidsecond indication after said time.
 12. A golf learning aid as recited inclaim 10, further comprising an actuator for being actuated by theindividual, the controller sending information to said indicator tocontinuously produce said second indication upon actuation of saidactuator by the individual.
 13. A golf learning aid as recited in claim10, said controller further capable of determining a time at which theindividual appears ready to perform a golf swing, said controllersending said information to said indicator to produce said firstindication when said angle is outside of said maximum spine angle rangeafter said time.
 14. A golf learning aid as recited in claim 10, whereinsaid sensor is an accelerometer capable of sensing acceleration in thedirection of gravity.
 15. A golf learning aid as recited in claim 10,wherein said maximum spine angle range is adjustable by the individual.16. A golf learning aid as recited in claim 10, wherein said indicatoris a sound generator including an earpiece adapted to be worn in an earof the individual.
 17. A golf learning aid as recited in claim 10,wherein the golf learning aid is worn on the individual's head.
 18. Agolf learning aid as recited in claim 17, further comprising a cap forfixedly supporting the golf learning aid on the individual's head, saidsensor, said indicator and said controller being mounted on said cap.19. A golf learning aid capable of being worn on an individual's head,comprising: a sensor capable of sensing an angle formed between an axispassing generally through the individual's spine and vertical; a soundgenerator capable of producing one or more audible sounds; a controllercapable of: a) monitoring said sensor and determining whether said angleis outside of a maximum spine angle range, b) sending information tosaid sound generator to produce a first audible sound when said angle isoutside of said maximum spine angle range, c) sending information tosaid sound generator to produce a second audible sound, said secondaudible sound being a metronome cadence repeating at a user-definedtempo, and d) receiving an indication from the individual causing saidcontroller to stop sending information to said sound generator toproduce said first audible sound and to send information to said soundgenerator to produce only said second audible sound.
 20. A golf learningaid capable of being worn on an individual's head, comprising: anaccelerometer capable of sensing a change in an angle formed between anaxis passing generally through the individual's spine and vertical; asound generator capable of producing one or more audible sounds; and acontroller capable of: a) monitoring said accelerometer and determiningwhen said angle is outside of a maximum spine angle range, b) sendinginformation to said sound generator to produce an audible sound whensaid angle is outside of said maximum spine angle range.
 21. A golflearning aid as recited in claim 20, said controller further capable ofdetermining a time at which the individual appears ready to perform agolf swing, said controller sending said information to said soundgenerator to produce said audible sound when said angle is outside ofsaid maximum spine angle range after said time.
 22. A golf learning aidcapable of being worn on an individual's head, comprising: anaccelerometer have an axis of sensitivity and a width dimensionperpendicular to said axis of sensitivity, said accelerometer capable ofsensing a change in an angle formed between said axis of sensitivity andthe vertical regardless of an angular orientation of the width dimensionaround said axis of sensitivity, said accelerometer mounted in thelearning aid on the individual's head with the axis of sensitivity beingcoaxial or parallel to an axis passing generally through theindividual's spine; a sound generator capable of producing one or moreaudible sounds; and a controller capable of: a) monitoring saidaccelerometer and determining when said angle is outside of a maximumspine angle range, b) sending information to said sound generator toproduce an audible sound when said angle is outside of said maximumspine angle range.
 23. A golf learning aid as recited in claim 22,wherein said accelerometer is mounted at or near an uppermost portion ofthe individual's head.
 24. A golf learning aid as recited in claim 22,further comprising a cap for fixedly supporting the golf learning aid onthe individual's head, said accelerometer, said sound generator and saidcontroller being mounted on said cap, said accelerometer being mountedat or near an uppermost portion of said cap when worn by the individual.25. A method of improving an individual's golf swing, comprising thesteps of: (a) sensing data relating to an angle formed between an axispassing generally through the individual's spine and vertical; (b)storing the data sensed in said step (a) in memory; (c) filtering outdata stored in said step (b) if the data is outside of a predeterminedrange; and (d) determining when the angle is outside of a maximum spineangle range based on the data stored in said step (b) and the datafiltered in said step (c).
 26. A method as recited in claim 25, whereinsaid step (c) of filter out data comprises the step of passing the datathrough a low pass filter to filter out any data above a predeterminedlevel.
 27. A method as recited in claim 26, wherein said step (c) offilter out data further comprises the step of passing the data through ahigh pass filter to find data below a predetermined level.
 28. A methodof improving an individual's golf swing, comprising the steps of: (a)sensing an angle formed between an axis passing generally through theindividual's spine and the vertical; (b) selecting a maximum spine anglefrom a range of maximum allowable spine angles; (c) determining whethersaid angle is greater than or lesser than said maximum spine angle; and(d) generating a first indication when said angle is greater than orlesser than said maximum spine angle.
 29. A method as recited in claim28, further comprising the step (e) of generating a second indication,said second indication being a metronome cadence repeating at auser-defined tempo.